The spinal column is comprised of interlocking vertebrae separated by intervertebral discs. The spine provides load-bearing support for one-half of the body's mass and it protects the nerves of the spinal column. The intervertebral discs provide shock absorption and facilitate the bending of the spine.
The combination of the vertebrae and discs at each vertebral segment allows for motion of the spine, in particular, flexing, rotation, and extension. The motion and support functions of the spine, in combination with the many interlocking parts and nerves associated with the spinal column, can result in back pain due to various reasons.
Most back pain arises in the lumbar region of the back. Back pain may result from strain on the back due to overexertion or may be due to poor posture or an injury to the spine. Chronic back pain is often due to a disorder originating in or from an intervertebral disc (i.e. discogenic pain). Such conditions can include bulging, herniated, or ruptured discs. A bulging, herniated or ruptured disc can trigger a response from proximate nerves, causing the pain sensation. Even after a herniated disc heals, the anatomy of the disc may not return to normal and may continue to cause pain. Even in the case where a disc is not herniated, chronic pain may present itself as people age because the annulus fibrosus begins to decay and the resulting small tears in the wall are infiltrated by nerves and blood vessels, causing pressure and chronic pain.
Intervertebral discs have an outer annulus fibrosus that surrounds the inner nucleus pulposus. A bulging or herniated disc is a situation where the nucleus pulposus herniates outward through the annulus fibrosus. The annulus fibrosus contains nerves, and the nociceptors and mechanoreceptors associated with the nerves respond to the disc herniation by providing a pain sensation. The pain receptors are concentrated along the posterior wall of the disc and the pain may result from the disc herniation but may also result from internal disc disruption, possibly involving partial tears in the multi-layered annulus fibrosus. Pain may also result from a disc fragment that remains exterior to the annulus fibrosus after the herniated disc recedes.
There are several non-surgical approaches that may be used to treat back pain. These include heating the affected area, certain types of exercise, medication, and electrical nerve stimulation. However, non-surgical treatments are often ineffective in treating chronic back pain.
There are a number of minimally invasive surgical procedures that are used to treat back pain with varying degrees of success. Intradiscal electrothermal therapy (IDET), also called intradiscal electrothermal annuloplasty, involves the application of heat directly to the inside of the disc via a needle that is inserted into the disc and heated at the desired location. Radiofrequency annuloplasty is another surgical method in which radiofrequency thermal energy is delivered to the affected area of the disc via a needle. Laser discectomy involves using a laser to vaporize a portion of the nucleus pulposus to decrease pressure in the disc. Thermal discoplasty utilizes a needle to deliver heat to the nucleus pulposus to decrease the pressure in the disc.
Other conventional surgical approaches are less minimally invasive. These include discectomy, in which all or part of the disc is removed in an effort to reduce pressure on the affected nerves; disc replacement, in which the disc is replaced with an artificial disc; and spinal fusion, in which the affected disc is removed and the two adjoining vertebrae are fused together.
Certain of the conventional treatments are designed to ablate or remove disc material to reduce the pressure in the disc. These include the discectomy procedures, including laser discectomy and radiofrequency or thermal discoplasty, also referred to as disc nucleoplasty. Other techniques attempt to treat the disc directly using thermal or radiofrequency energy, such as the IDET and radiofrequency annuloplasty procedures. It is not known exactly why the procedures that attempt to directly treat the disc, such as IDET, work. It is theorized that the methods may aid in the repair of tears in the annulus fibrosus, but the procedures may also destroy nociceptors in the treated area, thus disrupting their ability to sense pressure and transmit pain.
Each of the conventional approaches for treating back pain has certain disadvantages. In particular, each of the surgical approaches, even those that are minimally invasive, require penetration of the skin with surgical instruments to approach the area to be treated, even where the primary surgical instrument is a catheter or needle. Further, there are risks associated with the conventional surgical approaches that are inherent in any operation on the spine. Further still, the cause of the back pain may be inoperable due to the anatomy of the spine. Finally, all of the present approaches to treatment of back pain exhibit varying degrees of success, especially where the precise reason why the selected treatment method accomplishes its goal is not exactly known. Presently, spinal fusion, the most invasive of the conventional surgical approaches, is the preferred approach when less invasive methods are not successful.
There is a need for a back pain treatment that addresses one or more of the disadvantages of conventional approaches. In particular, there is a need for a back pain treatment that is non-invasive, less expensive than conventional surgical treatments, and able to treat back pain that is otherwise inoperable.
It would be desirable to provide a system and/or method that satisfies one or more of the aforementioned needs or provides other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.